Mr. Weenie is a German dachshund. He has black hair, a beige underbelly, and teeny, pudgy legs.

In the first film, he wore a knitted aqua sweater with light blue stripes, but when he first met the wilds, he tore off his sweater after shouting, "I've been living a lie!" and never wore it again for the remainder of the film.

In the second film, Weenie wore another sweater that Bob and Bobbie bought at a convenience store near the gas station, and he was still wearing it and his shirt in the third film.